MACROMOLECULES
·
2012
·
IF 5.167
Chuanzhuang Zhao,Guangcui Yuan,Charles C. Han
Poly(N-isopropylacrylamide) (PNIPAM) microgels are adsorbable to the surface of polystyrene (PS) microspheres in the experimental temperature range (25–40 °C) and can induce aggregation of microspheres through the bridging mechanism. The bridging mechanism proceeds in two elementary steps: the first is an adsorption (negligible desorption relatively) of free microgel to one microsphere surface, and the next is a reversible connection of the adsorbed microgel to another microsphere surface. The surface coverage is found as an important factor in triggering the stabilization, aggregation, and gelation of the mixtures. And most importantly, the nonnegligible dynamic disconnection of a bridge is the essential prerequisite for structure or state transition. For mixtures with the same concentration of microsphere, depending on the concentration of microgel, various transitions can be induced by changing temperature, including the transition from a weaker gel to a stronger gel, from a fluid to a bridging gel and from a depletion gel to a bridging gel.
研究领域:
材料科学
·
胶体化学
✓ 已验证
DOI
高影响因子
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
·
2025
·Vol. 122
·期 5
·e2417043122
·
IF 9.1
Danlong Li,Rogerio Manica,Zhixiang Chen,Shuo Wang,Qingxia Liu,Haijun Zhang
Bubbles present in saline water typically exhibit a prolonged lifetime, making them attractive for various engineering processes. Herein, we unveil a transition from delayed bubble coalescence to rapid bursting within about one millisecond in salty solutions. The key aspect in understanding this transition lies in the combined influences of surface deformation and ion surface excess instead of characterizing the ions alone. Only with a sufficiently deformed region trapped between the colliding bubble and fluid surfaces can the coalescence inhibition effect be maintained to cause the bouncing behavior. Thus, we quantify a consistent upper limit of ion transfer content required for instant coalescence under different salty conditions. Furthermore, we present numerical ranges associated with different bubble behaviors in terms of Eo, Re, and We and determine the critical values to predict bubble dynamics. Our findings shed light on the bubble coalescence principle in saline water and allow access to the regulation of coalescence time based on the requirement of technological applications.
研究领域:
工程学
·
流体力学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Huanhuan Gao,Jianzhong Liu,Zhihao Sun,Fan Zhang
In-situ assembly of three molecular perovskite energetic materials (DAP-2, DAP-4, and DAN-2) with ammonium perchlorate as the energetic eutectic oxidizer, the performance mechanism of hydroxyl-terminated polybutadiene propellant was investigated. This comprehensive study examined the thermal decomposition behavior and combustion-agglomeration characteristics of the eutectic oxidizers at pressures of 0.1–8.0 MPa. Experimental results demonstrated that the synthesized molecular perovskite energetic eutectic oxidizers exhibited significant redox reactions during thermal decomposition and combustion within the propellant. The reactions were accompanied by releasing superoxide ions, which notably enhanced combustion performance and energy release. The eutectic core-shell structure improved interfacial contact, leading to increased heat and mass transfer efficiency. As a result, shorter combustion times and increased burning rates were observed, with DAP-4 demonstrating the best overall performance among the five energetic materials. Additionally, the average agglomerate sizes ( D 50 ) for RDX, HMX, DAP-2, DAP-4, and DAN-2-based propellants near the burning surface were 161.11 μm, 92.51 μm, 40.64 μm, 30.30 μm, and 41.16 μm, respectively. The agglomeration degree of the propellants based on molecular perovskite energetic materials was significantly lower than that of the RDX and HMX-based propellants. This reduction in agglomeration is attributed to the thin molten skeleton layer and the high-temperature oxidizing gases produced by the molecular perovskite energetic eutectic oxidizers, which effectively suppressed aluminum particle agglomeration near the burning surface. This dual mechanism ultimately resulted in a significant enhancement in propellant performance.
研究领域:
材料科学
·
推进剂工程
·
热化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2021
·
IF 4.43
Mingzhang Song,Wei Luo,Shuibin Feng,Wenjun Jiang,Yukai Ge,Tao Liu
Long-chain branched polypropylene (LCB-PP) was generated by a melt grafting reaction with trimethylolpropane triacrylate (TMPTA) as the grafting monomer and zinc dimethyldithiocarbamate (ZDMC) or styrene (St) as the co-monomers. High-temperature size exclusion chromatography (HT-SEC) was used to characterize the molecular mass , molecular mass distribution and branching degree of the modified PP. Subsequently, linear and nonlinear viscoelasticity data were obtained by a small amplitude oscillatory shear (SAOS) test and uniaxial extensional viscosity measurement. The pressure balanced bubble-growth (PBB) model was used to calculate the critical coalescence radius (CCR) curves for PP to quantitatively correlate the viscoelasticity and foamability and evaluate the foamability of PP combined with batch foaming. It is shown that with increasing branching degree, the foam shows a better resistance to bubble coalescence , resulting in a more regular bubble structure and a higher expansion ratio. Moreover, viscosity should be controlled over an appropriate range for realising good foamability; otherwise, excessive viscosity can suppress bubble growth and limit the expansion ratio. MPPZ4 modified with 4 wt% TMPTA and 0.4 wt% ZDMC showed the best foamability. A combination of the PBB model and batch foaming experiment is used to quantitatively explain the contribution of LCB to foaming.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2022
·
IF 4.889
Chenghao Gao,Sida Ling,Zhuo Chen,Yundong Wang,Jianhong Xu
Droplet microfluidic technology refers to the technique of preparing and controlling microscale monodisperse droplets by shear force and interfacial tension of two immiscible phases accurately, which has a wide range of applications in biomedicine, chemical reaction enhancement, nanoparticle preparation, and other fields due to its efficient mass and heat transfer, easy manipulation, rapid response, and high throughput. In the application of droplet microfluidic technology, coalescence often occurs due to the structural complexity of microchannels, which limits the practical application performance. The mechanism of droplet coalescence has been widely studied in conventional reactors, among which the liquid film drainage theory is the most widely accepted. To achieve accurate control of the droplet coalescence process, there have been many studies on droplet coalescence in microchannels. A variety of microchannel structures have been proposed and the mechanism and influencing factors of double droplets coalescence have been explored. However, most of the existing studies on coalescence are based on cross structures, mainly studying the coalescence of double droplets in confined systems. There is still a lack of research on the coalescence process of droplet swarms, which is more widespread in practical applications. Therefore, this work used the rectangular expansion structure to realize the droplet coalescence and explored the effects of two-phase flow rate, continuous phase viscosity, surfactant concentration, and the size of expanding channel on the droplet coalescence behavior. The coalescence types, probabilities, and size distributions of microdroplet swarms under different factors were summarized. The time distribution of liquid film drainage in the droplet coalescence process and the influence of various factors on it were further analyzed based on the liquid film drainage theory.
研究领域:
微流控技术
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2022
·
IF 4.889
Yanjun Deng,Chunying Zhu,Taotao Fu,Youguang Ma
The effect of nanoparticles on droplet coalescence in microchannel was investigated experimentally. The interaction between acid-functionalized nanoparticles and polymers with complementary terminal functional groups facilitates the adsorption of particles at the oil–water interface. Three flow patterns were observed: squeezing coalescence, decompression coalescence and non-coalescence. The presence of nanoparticles significantly reduces the droplet coalescence percentage, and stable droplets could be obtained when the particles concentration increased to 1%. Furthermore, it was found that the film drainage time of squeezing coalescence was independent of the nanoparticles concentration. However, the film drainage time of decompression coalescence increases with nanoparticles concentration. Taking the influence of nanoparticles on the film drainage time into consideration, a new prediction model was proposed. Coupling the droplet contact time with the film drainage time, the critical capillary number for droplet coalescence was obtained. This work could provide important data and technical support for the application of nanoparticle-stabilized emulsions.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Aggregate
·
2021
·Vol. 3
·期 1
·e131
·
IF 0
Yu-Rong Zhang,Bi-Wei Meng,Bin Hao,Peng-Cheng Ma
A functional fabric with hierarchical structure consisting of basalt fibre fabric as a substrate and polyvinyl alcohol as a coating was developed, aiming at providing a low cost and high-performance way to separate highly emulsified oil in water. The coating functioned as a hydrophilic gate for the penetration of water in the emulsion, whereas the micro-channels formed in the fabric offered capillary force for the continuous flow of water. The synergy of these two materials led to the increase on the oil concentration in the liquid, which in turn enhanced the collision of emulsified oil droplets to aggregate into large ones in the emulsion and resulted separation from the water. Based on these findings, an aggregation-induced demulsification process was proposed to explain the above phenomenon, and the mechanism was confirmed by studying the distribution of oil droplets in emulsion with a controlled separation degree.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
·
2021
·
IF 3.186
Xin Huang,Limin He,Xiaoming Luo,Ke Xu,Yuling Lü,Donghai Yang
s The coalescence behaviors of two neutral droplets suspended in silicone oil under the alternating current (AC) and pulsed direct current (DC) electric fields are investigated by experiments and numerical simulations. The distribution evolutions of electric force and velocity field during the droplet coalescence under the AC and pulsed DC electric fields are analyzed. The relationship between electric field excitation and droplet interface response is illustrated. The equivalent response mechanism of droplets under the high-frequency AC and pulsed DC electric fields and under the DC electric fields is revealed. The relationship of droplet dynamic behaviors under the DC electric field and under the AC and pulsed DC electric fields are established. The critical electric field frequencies above which the shortest distance curves no longer change under the AC and pulsed DC electric fields are obtained. These new findings are significant for the optimization of electrostatic coalescence.
研究领域:
物理学
·
流体力学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2024
·Vol. 333
·期 3
·1155-1171
·
IF 1.5
Wu Lang,Liang Lili,Liu Datong,Wang Haijun,Lin Xiaoyan
Radioactive aerosols produced by nuclear accidents and decommissioning of nuclear power plants would cause tremendous radioactive damage to the environment and human body. The development of a radioactive aerosol suppressant is of great significance in the treatment of radioactive aerosols. In this study, a three-dimensional biomass-based polymer pectin-g-acrylic acid-acrylamide (pectin-g-poly (AA-co-AM)) SAP with high water absorbency and high agglomeration was prepared by solution polymerization. The results showed that the water absorbency of pectin grafted with acrylic acid and acrylamide reached 1064 g/g. Furthermore, under the synergistic effect of water absorption and agglomeration of the material, the sedimentation efficiency of simulated radioactive aerosol by 30 min after using suppressant is 91.21%.
研究领域:
环境科学
·
核能与辐射防护
·
高分子化学
✓ 已验证
DOI
高影响因子
Soft Matter
·
2016
·Vol. 13
·期 1
·119-124
·
IF 3.798
Zhou Liu,Xiangyu Fu,Bernard P. Binks,Ho Cheung Shum
In this work, we investigated the coalescence of liquid water marbles driven by a DC electric field. We have found that two contacting liquid marbles can be forced to coalesce when they are charged by a sufficiently high voltage. The threshold voltage leading to the electro-coalescence sensitively depends on the stabilizing particles as well as the surface tension of the aqueous phase. By evaluating the electric stress and surface tension effect, we attribute such coalescence to the formation of a connecting bridge driven by the electric stress. This liquid bridge subsequently grows and leads to the merging of the marbles. Our interpretation is confirmed by the scaling relation between the electric stress and the restoring capillary pressure. In addition, multiple marbles in a chain can be driven to coalesce by a sufficiently high threshold voltage that increases linearly with the number of the marbles. We have further proposed a simple model to predict the relationship between the threshold voltage and the number of liquid marbles, which agrees well with the experimental results. The concept of electro-coalescence of liquid marbles can be potentially useful in their use as containers for chemical and biomedical reactions involving multiple reagents.
研究领域:
胶体与界面化学
·
微流控技术
·
生物医学工程
·
药物递送
·
反应容器
✓ 已验证
DOI
高影响因子
Discover Food
·
2025
·Vol. 5
·期 1
·1-15
·
IF 3.7
Tian Zhen,Jin Huaizhou,Shang Xiaoxiao,Ma Qifei,Wang Weihong,Jin Shangzhong
The long-term stability of Pickering emulsions is crucial for their application in food systems. This study aimed to evaluate the stability degradation of oil-in-water (O/W) Pickering emulsions stabilized by whey protein isolate (WPI) and chitosan (CS), and to assess their applicability in reduced-fat mayonnaise formulations. Optical tweezers were employed to quantify the interaction forces between emulsion droplets during storage, in combination with microstructural observation and ζ-potential analysis. It was found that the O/W emulsion prepared with a 50% aqueous phase volume fraction maintained a stable droplet size over the storage period without significant changes. The ζ-potential decreased from 79.16 mV to 53.62 mV, while the maximum droplet contact force gradually decreased from 69 pN to 37 pN by day 45. By day 60, droplet coalescence was observed. Compared with traditional rice bran oil mayonnaise, the mayonnaise formulated using this Pickering emulsion exhibited superior mechanical stability and resistance to destabilization. In particular, the formulation with a Pickering emulsion-to-egg yolk volume ratio of 4:1 showed the best mechanical performance, with the droplet contact force gradually decreasing from 68 pN on day 0 to 62 pN on day 20. This study provides a rapid method for evaluating the stability of food systems, offering potential applications in the food industry.
研究领域:
食品科学
·
胶体科学
·
生物物理学
·
食品工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FLUID MECHANICS
·
2020
·
IF 3.333
Teng Dong,Fei Wang,Weheliye H. Weheliye,Panagiota Angeli
The delayed coalescence of drops with the interface between a moving aqueous layer and an oil phase is investigated in a novel flow channel. Drops are released onto oil–aqueous interfaces moving at velocities from $0~\text{cm}~\text{s}^{-1}$ up to $3.4~\text{cm}~\text{s}^{-1}$. The evolution of the drop shape, the film thickness between the drop and the bulk liquid, and the velocities of the drop surface and the bulk interface were measured with planar laser-induced fluorescence. As the interface speed increases, the drop coalescence is delayed. This is attributed to the lubrication pressure that develops in the draining film. This pressure was calculated by using the drop shape and the tangential velocities of the drop surface and the bulk interface, and was shown to increase with the interface velocity. The film forming between the drop and the bulk liquid has a dimple shape, symmetric about the centreline. With increasing interface velocity, the dimple shifts to the front part of the drop, resulting locally in a low pressure, which leads to film rupture. As the film breaks, ‘oil drops on a string’ formations are entrained into the water phase, which is rarely seen when a drop coalesces with a stationary liquid–liquid interface. The velocity fields in the drop were investigated with particle image velocimetry. It is found immediately after reaching the interface that the drops accelerate to reach the interface speed. Initially there is a strong internal circulation in the drops, which decays quickly as the drops approach the speed of the interface.
研究领域:
流体力学
·
界面科学
·
胶体与界面化学
·
微流控
·
生物医学工程
·
非平衡态物理
·
分子薄膜力学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）